Over at SlateJack Shafer talks about Gerald Posner's plagiarism. Weirdly Posner seems to be positing an "efficient markets" model of why he couldn't be a plagiarist:

Clearly, if I were a serial plagiarizer, I would have scanned my own drafts with such [plagiarism detection] software before submitting to the Beast.

The Ben Domenech case actually shows that yes, internet-age plagiarists can be pathologically dumb. There are plenty of cases of small-time plagiarists; my friend Randall Parker of FuturePundit was pointed to another blogger who was copying his posts almost verbatim. Small potatoes. But if you're a professional journalist,

you're going to get caught if you have any prominence if people can compare the text on the internet.

I think catching people plagiarizing like this is a good sign that there are some mental peculiarities at work here; cognitive biases if you will. This isn't cheating on college papers, unethical as it is, this is being unethical for short-term gains when there's a very high probability that you'll be caught and humiliated in public in the long -term.